This invention relates to a one way or non return valve which permits the flow of fluid within a pipe in one direction but prevents flow in the reverse direction and applies in particular to those valves comprising a short tubular body which accommodate a hinged valve member and a seat.
Previously proposed valves of the above mentioned type generally employ for their valve members discs or plates provided with hinges and springs in order that they may pivot. A disadvantage of these constructions is that the springs rust or break and the hinges become clogged with particulate matter present in the fluid resulting in the hinge becoming jammed. A further disadvantage is that the fluid openings are of restricted dimensions due to the configuration required to provide a landing or seat for the valve member resulting in blockages and restriction of fluid flow.